Meteoric smoke particle properties derived using dual-beam Arecibo UHF observations of D-region spectra during different seasons     

J.T. Fentzke  D. Janches  I. Strelnikova  M. Rapp 《Journal of Atmospheric and Solar》2009,71(17-18):1982-1991

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Holocene landscape evolution and its impact on the neolithic and bronze age sites in the Shangqiu area,Northern China     

Zhichun Jing  George Rapp  Tianlin Gao 《Geoarchaeology》1995,10(6):481-513

The Shangqiu area, situated on the alluvial plain of the lower Yellow River, is traditionally considered the center of the predynastic and early Shang culture. Archaeologic remains dating to predynastic and dynastic Shang periods, however, have remained elusive. The current pattern of Neolithic and Bronze Age sites is characterized by their upland settings; and it has been often assumed that the area had the same landscape from the Neolithic through recent historic time. The potential impact of geomorphic processes on these early sites has been hardly considered in developing archaeologic models of temporal and spatial distribution of these sites. This article first presents a reconstruction of the Holocene floodplain history in the archaeologically significant area. On the basis of stratigraphy and sedimentology, a Holocene landscape evolution model is constructed to explore the interrelationship between evolving landscape and archaeologic record of the Neolithic and Bronze Age. The prolonged landscape stability from very late Pleistocene or early Holocene to 2000 yr B. P. provided potential Neolithic and Bronze Age human occupation with a favorable physical environment. After 2000 yr B. P., the hydrologic regime changed and the floodplain experienced 2-3 m of gradual vertical accretion during the following millennium. In response to the dramatic change of hydro-logic regime after the early 12th century A. D., a new floodplain formed by dominantly overbank deposition, and the old floodplain surfaces are covered by as much as ten meters of the younger alluvium. As a result, a pronounced effect has been imposed on the preservation, visibility, and discovery of the Neolithic and Bronze Age sites, including those sites of predynastic and early Shang phases. Thus, much difficulty has been imparted to our understanding of the configuration of these early archaeologic sites. This study demonstrates the usefulness of landscape reconstruction in developing settlement models of Neolithic and Bronze age sites in the area.  相似文献   

Dynamic Topography Estimates Using Geosat Data and A Gravimetric Geoid In the Gulf Stream Region   总被引：1，自引：0，他引：1  

Richard H. Rapp  Yan Ming Wang 《Geophysical Journal International》1994,117(2):511-528

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The determination of a one year mean sea surface height track from Geosat altimeter data and ocean variability implications     

Yan Ming Wang  Richard H. Rapp 《Journal of Geodesy》1992,66(4):336-345

One year (November 1986 to October 1987) of Geosat altimeter data with improved orbits produced at The Ohio State University has been used to define sea surface heights for 22 ERM and one year averaged Geosat track. All sea surface heights were referenced to the single reference track through the application of geoid gradient corrections. The root mean square (RMS) gradient correction was on the order of ±1 cm although it could reach 20 cm with data points in trench areas. 10 values used to form the mean were considered. Although this study was initially driven by a need for a good reference sea surface for geodetic applications the formation of the reference track yields information on the variability of the ocean surface in the first year of the Geosat ERM. The RMS point variability was ± 12.6 cm with only a very small number of values exceeding 50 cm when a depth editing criteria was used. Global plots of the sea surface variability clearly reveal the major ocean currents and their variations in position in the year. Examination of the 1° × 1° averaged sea surface height variations show average and maximum variability values as follows: Gulf Stream (29 and 50 cm); Kurshio Current (24 and 49 cm); Agulhas Current (24 and 52 cm) and the Gulf of Mexico (18 and 31 cm). These magnitudes may be dependent on the radial orbit correction procedure. To investigate this effect sea slope variations were also computed. These results also showed clear current structures but also high frequency gravity field information despite efforts to average out such information. The data described in the paper is available from the authors for numerous other studies, some of which are suggested in the paper.  相似文献   

Meeting of the International Geoid Commission     

Richard H. Rapp 《Journal of Geodesy》1990,64(3):301-301

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Metamorphic assemblages and the direction of flow metamorphic fluids in four instances of serpentinization     

Dr. I. Barnes  John B. Rapp  James R. O'Neil  Richard A. Sheppard  Arthur J. Gude III 《Contributions to Mineralogy and Petrology》1973,38(1):80-80

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A comparison of altimeter and gravimetric geoids in the Tonga Trench and Indian Ocean areas     

Richard H. Rapp 《Journal of Geodesy》1980,54(2):149-163

A gravimetric geoid computed using different techniques has been compared to a geoid derived from Geos-3 altimeter data in two 30°×30° areas: one in the Tonga Trench area and one in the Indian Ocean. The specific techniques used were the usual Stokes integration (using 1°×1° mean anomalies) with the Molodenskii truncation procedure; a modified Stokes integration with a modified truncation method; and computations using three sets of potential coefficients including one complete to degree 180. In the Tonga Trench area the standard deviation of the difference between the modified Stokes’ procedure and the altimeter geoid was ±1.1 m while in the Indian Ocean area the difference was ±0.6 m. Similar results were found from the 180×180 potential coefficient field. However, the differences in using the usual Stokes integration procedure were about a factor of two greater as was predicted from an error analysis. We conclude that there is good agreement at the ±1 m level between the two types of geoids. In addition, systematic differences are at the half-meter level. The modified Stokes procedure clearly is superior to the usual Stokes method although the 180×180 solution is of comparable accuracy with the computational effort six times less than the integration procedures.  相似文献   

Comparison of the potential coefficient models of the Standard Earth (II and III) and the GEM 5 and GEM 6     

R. H. Rapp 《Journal of Geodesy》1975,49(4):443-445

Sans résumé

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Comparison of the potential coefficient models of the Standard Earth (II and III) and the GEM 5 and GEM 6

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La rédaction du Bulletin Géodésique s'excuse auprès de l'auteur et de sas lecteurs pour cet oubli involontaire.

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The online version of the original article can be found at  相似文献   

Ellipsoidal density models and hydrostatic equilibrium: Interim report     

A. Marussi  H. Moritz  R.H. Rapp  R.O. Vicente 《Physics of the Earth and Planetary Interiors》1974,9(1):4-6

From the point of view of consistency with the Geodetic Reference System 1967, it would be desirable that the boundary surface of a Standard Earth Model is an exact equipotential ellipsoid. This is incompatible with the requirement that it be a figure of hydrostatic equilibrium. The report investigates the relation between equipotential ellipsoids and equilibrium figures. The principal conclusion is that it is possible to find an ellipsoidal model that has the same distribution of density and flattening (more precisely, of the parameter f′ as defined in the paper) as a hydrostatic model, the deviations being only of second order in the flattening.  相似文献   

Satellite orbit computations using gravity anomalies     

Richard H. Rapp  Reviewer M. Burša 《Studia Geophysica et Geodaetica》1972,16(1):1-9

Summary A typical geodetic satellite orbit has been computed by numerical integration for a period of thirty hours. The gravitational potential of a standard orbit was represented by the SAO 1969 Standard Earth potential coefficients taken to degree 18. Other orbits were generated using the generalized Stokes' equations and the coating method applied to gravity anomalies and surface densities, in 5°, 10°, 15° and 30° equal-area blocks, derived from the given potential coefficients. The differences between these orbits yield the position differences to be expected when representing the potential field by using gravity data instead of potential coefficients. Using 10°, 15°, and 30° blocks and the generalized Stokes' equations, the position error at the end of thirty hours was 89 meters, 224 meters, and 2060 meters respectively. This error is primarily due to the integration error in computing the gravitational field by summation over a finite number of areas.  相似文献